1. Technical Field
The disclosure relates to a sensing device and manufacturing method thereof. In particular, the disclosure relates to a sensing device and manufacturing method thereof having chambers formed by multiple stacking substrates.
2. Related Art
In general, the sensing element in a micro-electromechanical sensing device should operate in a sensing chamber of specific environmental condition in order to obtain a stable operation and a precise output result. The environmental condition within the sensing chamber accommodating the sensing element varies based on the requirements of different sensing devices. For example, the effect of the vibration damper of sensing device to the ratio of the vibration frequency to sensing noise signal has to be considered in some sensing devices. Thus, the sensing element is disposed in a high sub-atmospheric environment or of vacuum airtight chamber in order to reduce the energy consumption due to the air damping. In addition, some sensing elements need the assistance of a proper air damping of vibration so as to properly, stably and instantaneously output signal. Thus, those sensing elements are preferably disposed in a chamber of specific pressure (such as an atmospheric pressure) for operating. Besides, some sensing elements has to be disposed in a sensing chamber having a gas with specific mixed composition or a gas with specific single composition for operating to achieve the improvement or compensation of the specific sensing characteristic.
In the airtight chamber mentioned above, the environmental condition within the sensing chamber will not react with the outside environment such as air intake or outlet. However, except the airtight chamber, there are some open-type chambers capable of connecting with the outside environment, wherein sensing elements, such as pressure gauges, gas sensors or the like, within the chamber can react with the outside environment in order to detect specific physical quantities of the outside environment.
However, although the aforementioned different types of sensing elements can be respectively and independently packaged by their own packaging processes in chambers of different environmental conditions to form sensing devices, the integrating of the different types of sensing elements is however restricted by the requirement of different environmental conditions of chamber. When more than two sensing elements having different environmental conditions requirement have to be integrated to the same semiconductor substrate, how to form a plurality of sensing chambers having different environmental conditions independently on the same semiconductor substrate is the existing difficult technical problem.
On the other hand, in conventional, methods of re-soldering solder or deposition filling material or the like are common used to fill the channel of the chamber in order to form an airtight chamber. However, those methods may lead to the filling material being deposited on the sensing element or polluting the interior of chamber and the sensing element failing to operate. Furthermore, since these sorts of solders or sealing materials are rather loose in structure, the sealed chamber is unable to achieve a good tightness and the environmental condition within the sealed chamber also can not be ensured.